Primary Retinal Detachment
Primary Retinal Detachment
Primary Retinal Detachment
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
154<br />
search for compounds with heparin-like qualities on growth factors,<br />
but without the potential hemorrhagic issues. It is known that<br />
fractionation of longer chains of heparin into smaller molecular<br />
weight fragments causes loss of some of the anticoagulant activity<br />
while preserving the ECM effects.As a result, low-molecular-weight<br />
fractions of heparin with a molecular weight of 5000 or less retain<br />
their ability to catalyze the inhibition of Factor Xa, but lose their<br />
ability to directly inhibit thrombin [49]. When low-molecularweight<br />
heparin was introduced into the infusate during vitrectomy<br />
in an animal model, fibrin formation was markedly reduced without<br />
any coincident increase in intraocular hemorrhage [50]. Use of<br />
5 IU/ml of low-molecular-weight heparin in the infusate during<br />
creation of an experimental model of proliferative vitreoretinopathy<br />
reduced the rate of traction detachment from 77% to 28% at<br />
3 months [51]. These encouraging results led to the inclusion of lowmolecular-weight<br />
heparin in the infusate, along with 5-FU, which<br />
was studied in the prevention of PVR in humans [15, 42, 50, 51].<br />
In another important PVR trial, when conventional heparin<br />
(1 IU/ml) was combined with a steroid dexamethasone (5 mg/ml)<br />
in the infusate, there was a slight increase in the retinal reattachment<br />
rate compared with controls from 65% to 80% in addition to<br />
a reduction in the rate of reproliferation from 26.5% to 16%.A mild<br />
increase in the rate of hyphema and vitreous hemorrhage was<br />
seen, although it was not judged to be clinically significant [33].<br />
Summary<br />
7 Pharmacological Approaches to Improve Surgical Outcomes<br />
Pharmacological methods remain a promising potential adjunct to<br />
the successful treatment of retinal detachment. In addition to conventional<br />
strategies, including adequate pupillary dilatation, control<br />
of inflammation by anti-inflammatory agents, and intraocular<br />
pressure by ocular hypotensive agents, drugs may play a further<br />
role by inhibiting other late complications. These include proliferation<br />
and macular edema. Steroids, fluoropyrimidines, and he-